text:
If jet engines did leave chemtrails, wouldn't the chemicals cause adverse reactions in the engines?
Please note, this question does not call into question whether or not the conspiracy theory is true or untrue, but the feasibility of certain chemicals being used as fuel additives in order to make the theory viable.
Chemtrail conspiracy theorists believe that there are certain additives being put into jet fuel to spew out [nano-]particles that rain down on us, for means that are being kept secret.  The hypothesized reasons behind 'chemtrailing' range anywhere from weather modification, population reduction, and sunlight blocking to reduce the earths temperature hence combatting global warming.
Some popular agents that are called into speculation:

Aluminium based aerosols
Mono-atomic gold
Barium

My question is, wouldn't these additives, chemicals, etc, cause adverse reactions inside the jet engines, if the turbine is the actual catalyst supposedly spraying these things?

Mold spores, blood, or other organic things probably wouldn't survive the high temperatures/pressures. Anything else you would have to figure out what it would be after being diluted in jet fuel (basically refined kerosene) and burned. So what could you really successfully accomplish (or even be worth trying) with a fuel additive that could have an effect like the conspiracy theorists are speculating... Most of us are pilots or other aviation related workers or enthusiasts. I have a Master's of Aeronautical Science but I never even took chemistry except in High School..

I don't think conspiracy theorists are concerned about what engine manufacturers say might or might not damage the engine.

Nor are they overly concerned with the truth.  It's the tin foil hat brigade.  Nothing to see here, folks, just move along....  (just my opinion.)

I'll link the related question from skeptics here

The suitability of this question here is being discussed in meta:  Why was my question closed?

The chemtrail additives are aerosolized into the exhaust stream, duh.

Jet fuel is seldom if ever pure hydrocarbon molecules. It's got a lot of other stuff mixed into it to improve the properties. I'm going to quote Shell for the sake of examples:

Antioxidants (gum inhibitors) must be used in Avgas to prevent the
  formation of gum and other antioxidation products. Jet fuels, which
  are inherently more stable than gasolines, may contain them, depending
  on the treatment process used during manufacture.
A metal deactivator - now rarely used - may be added to nullify the
  effects of dissolved trace metals, especially copper, which can impair
  the thermal stability of jet fuels.
Corrosion inhibitors can be used to reduce corrosion in fuel system
  and improve the lubricity - lubricating properties - of jet fuels.
Fuel system icing inhibitors reduce the freezing point of any water
  that may be in the fuel system and prevent the formation of ice
  crystals that could restrict fuel flow. They are mandatory in military
  Jet but are not used in civil aircraft that have fuel heaters. They
  may be added to either Jet or Avgas during the fuelling of small
  aircraft.
Static dissipater additives minimise the hazardous effects of static
  charges that build up during movement of jet fuels. They are sometimes
  used in Avgas as well. Source

Further analysis
No practical application:

Aluminium based aerosols, Mono-atomic gold, Nano aluminum-coated fiberglass, Radioactive thorium, Cadmium, Chromium, Nickel, Desiccated blood, Mold spores, Yellow fungal mycotoxins, Polymer fibers, Barium.

Useful additives from your list:

Ethylene dibromide- Anti-Knock agent in aviation fuel.
Alumium: Derivatives containing it have been used.

Many of the materials you list might have the very real potential to (seriously) damage jet turbines and piston engines if mixed in during extended use.

Not so sure about "desiccated blood" (eek!), but polymer fibres sound like something that would seriously screw up a jet engine, especially when heated to the temperatures inside one.

Temperatures inside the burner can of a jet engine are 500 - 600 degrees Celsius.  I wouldn't worry much about biologicals in the jet fuel.

@SkipMiller … and that's just the temperature that hits the turbine. The active flame has at least three times as much and does not melt the engine only because colder air is blown through small holes in the combustor lining to keep the flame from actually toughing it. Obviously not all the air reaches that temperature, but the fuel does.

Mixing things in with aviation fuels that aren't purpose-engineered for the aircraft fuel system environment is useless at best and harmful to the airplane and/or engine at worst.
Of your list:

Mycotoxins, blood-based stuff, and spores would simply burn up.
Live biologicals are worse -- they can cause trouble even before they get the chance to burn up.  For instance, they can produce corrosive organic acids, gnaw on plastic and rubber parts, or form biofilms and mats that work wonders for clogging orifices.  Also, fuel system icing inhibitors have biocidal effects as they deprive any would-be-living-things in the fuel of much-needed water.
Metals have an annoying habit of catalyzing reactions that form gummy deposits in fuel system parts; in fact, additives are used to get metal ions in the fuel into a sequestered state where they won't cause gummy, gunky trouble.  Civil Jet-A doesn't use them as often because refiner QC and QA are better  than they were about keeping metal ions out of the fuel to begin with, but they are a key ingredient in the +100TS additive package used in military JP-8.
Particulate additives are a particularly bad choice as they have the strong potential to clog orifices and jam fine moving parts in aircraft fuel system control elements, which can have serious to catastrophic consequences.  This rules out polymer fibers and coated fiberglass.

As a sidenote -- ethylene dibromide is only used in aviation gasoline, which is a niche fuel in the current commercial aviation world (some Part 135 operators use it, but that's really about it -- turbine reliability is too convincing an argument to avoid for all but the smallest aircraft used in even air taxi and commuter airline service).  Considering the airplanes that burn it, it can be scratched off the list fairly safely.
In conclusion: anyone who tried to "spike" some Jet-A with a sooper sekret mystery additive would do nothing useful at best, and wind up getting blamed for a smoking hole in the ground at worst.  Imagine being the CIA and having the NTSB trying to roast you over a top secret program...

NTSB isn't the worst. It is still an US agency, so they could have some leverage on it. Now consider it being BEA (it it gets in Airbus, they get involved), AAIB (if it has Rolls-Royce engines, they get involved) or anyone else (whatever country the operator is from gets involved)—like MAK…


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I have a document referring to aircraft with maximum takeoff weight of 45000T. Is this an error?

I got the attached document from http://www.aisthai.aviation.go.th/.
This document refers to aircraft with MTOW 45000T.
Is that 45000 tons? That's pretty heavy for me. Or am I interpreting the document incorrectly?

the abbreviation of a tonne is a small t it could mean [45k Tablespoons][http://en.wikipedia.org/wiki/Tablespoon) but that would be silly

It stands for metric tons, as indicated in the "GEN 2.1 Measuring system, aircraft markings, holidays" section of the AIP that you linked to as one of the units for mass.
That being said, the number format appears to be wrong and they most likely intended 45.000 metric tons, which works out to about 99,000 lbs. and is a somewhat common point to use for aircraft classification in other countries.

My guess is that you're correct. Just for the heck of it I sent them an email asking for verification. I'll report back if they answer.

That is not 45000 but 45,000.
Seeing that the comma has been used for thousands in the fuel trucks capacity, it could be a copy-pasted typo.

Yeah but why comma and not decimal. Is it standardize? Any other reference?

@vasin1987 in some countries the comma for decimals IS the standard. anyway, answer edited.

I wonder if the number is right, but the units are wrong? 45,000 tons sounds like a lot, but 45,000 kg or lbs is a lot more reasonable.

I checked to see if this might be referring to tare weight but: a) I have never heard of tare weight being used in an aviation context; b) tare weight is the empty weight of an box or shipping container - possibly relevant to an aircraft, but a maximum empty weight limit?  I don't think this concept has legs in this context; and c) the official abbreviation for tare weight is tw.  This comment doesn't help find the answer, but it does help define what the answer is not!

@egid that would be the typo I mean: a comma instead of a full stop (would be 45 tons)

but adding those extra digits is still strange, most of the time when a MTOW is displayed it's with 2 maybe 3 significant digits never 5

According to this entry, http://en.wikipedia.org/wiki/Decimal_mark
Thailand officially uses the "point" as the decimal delimiter and the "comma" as the thousands separator.  So there's either a typo or a reallllly big plane...

In English, 45,000 is 45000.

In the VFR flights section, they put 10 000 ft. No comma at all. /shrug

Also, in the tables and codes section, all mass (weight) is either kilograms or metric ton.

@CGCampbell so you agree with me that it could be a typo, or I misunderstood you?

@Federico yes, however I'm actually going through all of the addendums now

They clearly can't have meant 45 thousand tonnes. Even the likes of the AN225 and the A380 are nowhere near that big.
In parts of continental europe they use the comma as a decimal seperator. All too often I see datasheets (I work in electronics) where the text is in english but the numbers are using european format. However the fact that there seems little reason to use three decimal places for a number like that and the fact they use , as a thousands seperator in the fuel section makes me think this probablly wasn't the source for the original error.
I suspect whoever wrote it somehow mixed up kilograms and tonnes and this may have been compounded on proofreading by the above issue of some countries using decimal commas.

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How are avionics updates delivered?
I'm idly curious to know what type of physical storage medium (e.g. is it a "mini-CD", USB key, a little hard drive, maybe a tape) is used for delivering avionics updates, for an as-recent-as-possible aircraft?
For big (e.g. commercial airliner) and/or military?
I guess you're not downloading updates from the internet?
Could you (optionally) also paint a vague public-domain picture of how the "chain of trust" works? Or is the delivery route (media passing hand to hand) not especially secure, and instead all the chain of trust is in built-in digital signatures?

used for delivering avionics - do you mean updates?

I don't know. Does that mean the question is too broad? I guess I mean any field updates, yes, after the plane and its components have left the factory.

It might be too broad.  I am familiar with 2 methods, but these may well be specific to manufacturers/systems.  An a 1990s vintage FMC, you accessed a hidden settings page through key presses documented in the maintenance manual but not the user manual.  You could update the software from a "dongle", plugged into a port in the avionics bay by providing a password code which was unique to the system and operator.  I am guessing that the dongle has been replaced by USB key in more modern implementations.  The data was encrypted by the manufacturer and decrypted on loading by the FMC.

Another system used line replaceable boards with the EEPROMs (read only memory that retains it's contents when powered off and can be reprogrammed) which plugged into a chassis accessed via a maintenance panel.  In this way, the entire software load was replaced rather than simply being updated.  If I read your question correctly, you may be assuming that updates are somehow done over a network (hence your question about chain of trust) which whilst I don't know, I suspect does not happen since security would be a big concern.

@Simon Thanks for that historical picture. "you may be assuming that updates are somehow done over a network" -- I'm assuming the opposite at the moment, and that there is therefore some apparently old-school (i.e. physical) storage/distribution medium involved (including for example replacing EEPROMs). I am alternatively willing to be surprised, if you want to tell me that instead it is now done via some secure and/or insecure network.

@Simon Even if they're not 100% up to date, your comments do seem answer-worthy to me.

@ToddWilcox I am one of the "long of tooth" around these parts ;)

@Simon There's been a big recall of Jeeps recently, too. "I really doubt that a network is involved." There's more than one network (i.e. I'd expect the IFE is pretty separate). Theoretically you could have your avionics air-gapped under normal conditions, and for maintenance insert a network connector which establishes (I don't) a VPN link to the manufacturer. I was just curious. I thought maybe there'd be some clue in the public domain, perhaps in manufacturers' sales brochure or etc.

The Rockwell Collins FMS units found in many large airliners are updated via USB stick. you can find a nice video here on how its done. Most GA planes use SD cards (or other similar card formats) these days. Some people chose to use apps like ForeFlight on their iPad which is updated via the internet.
As for the "chain of trust" Rockwell Collins requires a subscription to their FMS database downloads however they are downloaded straight from the internet. There is a list of addendum and alterations which some airlines apparently have. In reality the medium is not "secure" as you mention but tampering with it would be in violation of some FAR (I'll try and find the one) since you would potentially create a hazardous situation. I'm sure airlines and A&P shops are diligent about these updates the same way they are about any maintenance. I'm not sure if there is any software level encryption on the data.
For apps like ForeFlight and some of the more GA directed markets (that are not using full FMS systems) the FAA makes all of their charts available in digital form for free. I would assume this is where places like ForeFlight get their data and then, as a user, you download it from the ForeFlight servers. Again you pay a subscription to ForeFlight to guarantee that these things are on line and up to date. Again this is all not very secure (in a manner of speaking) and you are relying on ForeFlight to not tamper with the maps. When talking about updating the maps in a GA plane chances are it's your plane and you are responsible to ensure its safe operation. Garmin seems to make their downloads available right on their site.

I'm confused as to how this answer is correct.  The question specifically asks about Avionics (like EFIS for example) and this answer is all about maps for the FMS.  They aren't really the same thing and very very different standards for quality assurance.  I really don't think this answers the question as stated.

FMS was used as an example, being one of the older digital units out there its a nice example of how things have changed over time as well. Take for example the G1000 Flight deck, that is updated all via SD cards following a similar method as the FMS.

It most likely doesn't use encryption, but digital signatures which would prevent tampering. It might use obfuscation though to make analysis (and theft of intellectual property) more difficult, though.

Different kinds of Software
We need to distinguish between several categories of software.

Field-loadable software (FLS) is, loosely defined, any software which can be reconfigured, updated, or uploaded by technicians and manufacturers, like the avionics software.
Aeronautical databases are not categorized as field-loadable software and are treated separately in regulations. These aeronautical databases may be a terrain database, a navigation database, an obstacle database, or an airport map database.
Factory loaded software, which is assumed not to change during without replacing the device it's on.  To change factory-loaded software you often have to break a seal and flash the memory.  It may also be on read-only memory like an EEPROM.

Thanks to advances in FLS practices, field-loadable software is being used in many places where factory-loaded software had been used previously and frequent software updates are becoming common on most systems. Software on virtually any part can be field-loadable if it follows safety and integrity measures.
Aeronautical databases are treated differently in part due to the difference in update frequency. An aeronautical database must change frequently (often more than once a month), while avionics updates are less frequent and may be less than once a year (especially because the entire aircraft configuration, software included, must be certified).
What steps are taken to update software?
A patent by Airbus explains the process excellently, even with diagrams in French:

The first step is managed by the manufacturer of the aircraft. The latter decides upon a required modification for the aircraft it has constructed. It develops the modification for the solution found and certifies it with the certification authorities. The manufacturer thus shows that the new configuration proposed is compatible with the environment and with the configuration of the aircraft for which the modification is destined.
  Once the solution has been developed and validated, the manufacturer prepares a pack, referred to as service bulletin, containing a description of the operations to conduct to perform the modification of the aircraft and also a physical element containing the software to change and furthermore containing corresponding documentation. The physical element containing the software depends on the size of the software and it may for example be a USB key (USB standing for “Universal Serial Bus”), a CD/DVD, etc. This pack is delivered physically to the company concerned that operates the aircraft. This delivery may also be performed electronically.
The second step is carried out under the responsibility of the operator of the aircraft, for example an airline company, or, when the aircraft is under heavy maintenance under the responsibility of the maintenance organization authorized for that. Similarly, this step may be performed by an authorized MRO (standing for Maintenance Repair Organization) when the aircraft is transformed for a change of operator. This is typically of the case for an aircraft hire company.
  The operator receives the service bulletin and transfers it to a technical center (FIG. 1) in order for the operator to allocate and verify the compatibility of the service bulletin received with the environment of the aircraft of its fleet. Once the verifications have been performed and the service bulletin validated, a work request is sent to the maintenance management department of the operator's fleet. That department then defines the times (stopover, heavy maintenance visit, etc.) at which the aircraft may undergo that update and provides the workshop with the software element to install on the aircraft (USB key, DVD, etc.).
A maintenance workshop of the airline company or of a maintenance repair organization performs the requested task and downloads the software which is in the DVD or USB key (or other medium). The action is recorded and the configuration repository of the aircraft is updated. Of course, the technical center (and possibly other departments concerned) is kept informed of the upgrade which has just been carried out.

Navigational database updates were traditionally updated using a similar process according to this Honeywell patent:

... the information contained in the navigation database changes on a very frequent basis as new navigation aids are created, old navigation aids are retired, airports add or retire runways, or the like. Accordingly, government agencies such as the United States Federal Aviation Administration (FAA) typically require that aircraft update navigation databases on a regular basis, such as every twenty-eight days. Other components (such as global positioning systems (GPS)) may also make use of periodic data upgrades.
Conventional techniques of updating databases have been cumbersome and time consuming. Typically, a customer (such as an airline) obtains a diskette containing the upgrade for a particular aircraft type from a database or component vendor. The customer then duplicates the diskette and distributes copied diskettes to service technicians, who then go to individual aircraft and manually load the data update using a specialized data loader...

See also https://www.google.com/patents/US20030208579 for an example of how in-flight entertainment systems are traditionally updated.
What media is used?
A variety of media has been used over time since storage media changes quickly. Physical media like CD's are quickly being replaced by high integrity network updates due to the cost benefits involved.
A patent for a "Method for controlling customer-implemented data updates" explains how this process was done historically:

Originally, airline maintenance personnel upgraded flight management
  computers by using an ARINC standard 603 portable tape upload device,
  but such tape loaders were clumsy and slow. Manufacturers then
  progressed to data loading computers that were based on ARINC standard
  615 (Data Loader standard), which is in essence a software protocol
  layered onto an ARINC standard 429 data bus. ARINC 615 data loaders
  abandoned the tape format of ARINC 603 in favor of a 3.5-inch floppy
  diskette medium for transferring data and software... The
  software or data for these updates has grown increasingly more complex
  as the systems in aircraft provide more functionality to the cockpit
  crew and traffic control.

In more recent history, "The media used to load FLS changes with time. In the early 1990's, 3.5 inch diskettes were used.  For example, the original Boeing 777 carried around binders full of floppy disks.  The technology has moved on to compact disks (Cds), digital video disks (DVD's) thumb drives, mass storage devices, and even local area networks (LANs)" source
Another patent discusses in detail the way that software can be loaded over LAN.  The image below is from the patent.  The principles are much the same:

The software must be part of a certified aircraft configuration
Aircraft in the fleet are checked over the network to see if their configuration is out of date or incorrect
Aircraft are updated to a new configuration when and only when the operator initiates the update
A reliable integrity check like a CRC is in place to make sure the update over LAN was successful

What safety and integrity measures are taken?
Fun fact: Field loadable software is considered a part, and therefore the configuration management that applies to parts also applies to software updates.  The updated software must be certified for the aircraft configuration it's on, must have a part number which can be verified, and must appear on the bill of materials for the new aircraft.  Sometimes an entire device will have a new part number when its software is updated, or sometimes the software has a separate part number that's updated while the hardware retains its own part number. Any modifications to the software must go through a change-impact analysis and recertification.
The field loadable software must be certified for the device and aircraft it's being loaded on and there must be checks on the software loading process, the software itself, the software part  number.  DO-178C specifically specifies that:

there must be protection from inadvertent loading (which also means that unlike Windows, it won't force you to update at the worst
possible time)
there must be detection of failed, partial, or corrupted loads
you must be able to reliably determine that the currently loaded software and all its files are correct (for example, by using a CRC)
if a display mechanism is used to display the software load, the display must be accurate and reliable

Integrity checks must have a level of reliability, similar to other reliability check in aircraft.  This often means that the software loading must have a 10^-9 chance of corrupting software or incorrectly indicating the software load is correct.  You can instead qualify the tool used to load the software, but this is less common than showing that the integrity checks are reliable.
Chain of Trust for Aeronatuical Databases
For aeronautical databases, safety levels and error checking are also seriously considered.  Each particpant in aeronautical database creation and transmission must have a compliance plan, configuration management, error checking, a method to ensure unauthorized changes don't occur, and quality management.  As outlined in AC 20-153, The FAA will provide a Letter of Acceptance (LOA) to each particpant in this process indicating their compliance with regulations like DO-200A.  Aeronautical data must meet various standards as applicable like ARINC 424 and DO-291B, but a discussion of those is out of scope of the question.
For more information:
Chapter 5 of FAA Order 8110.49 specifically addresses approval of field-loadable software.  RTCA's DO-200A is the standard for preparing and transmitting Aeronatuical databases from a regulated data provider to the operator of the aircraft.  See also FAA AC 20-153 for certifying compliance and granting letters of Acceptance to DO-200A.
I have heavily referenced "Developing Safety-Critical Software" by Leanna Rierson.  I suggest you reference this or another book.
Disclaimer:  I am not a DER or engineer for the data loading process and so this information is for reference only. For technical work please consult the source documents and a DER instead of relying on this information.

Updating A380 navigation using flash drives

In general aviation applications, navigation database and software updates are downloaded over the internet from the avionics manufacturer, and stored on an SD card, which is later inserted into an SD card slot in the bezel of the avionics in the aircraft.
Downloads are restricted to registered subscribers.

So, the update is essentially delivered over the internet. This raises an important question, is there any cryptographic signature on those software package; and the equivalent of Secure Boot mechanism, that is now common on new PCs.

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Does this fuel leak from the carburetor of a Cessna 172E need immediate maintenance?
Consider:

I'm concerned with a fuel leak I've developed on my Cessna 172E in the past three weeks and appears to be coming from the carburetor. There is even some fuel in the air breather near the bottom. An A&P said it’s nothing to be concerned about and everything checked out good he said.
I'm extremely new to this area and don't think I should be seeing blue streaks on the front nose wheelpant and blue streaks coming from the carburetor and air breather filter. It is not a noticeable leak during engine running and appears to only be leaking after engine is shut down for just a short time afterward.
I have also noticed I have a 150 rpm loss at full power on the ground. It used to be almost 2400 rpm on ground and now it’s about 2250 rpm. For the record, it has been getting below freezing the past month and I noticed all this after we did a shortfield landing on a grass strip in Oklahoma.
I'm so concerned that I am scheduling the annual now instead of waiting two more months when it’s due and am also scheduling with a new A&P. What is your opinion? Or am I just being too cautious?

If I see something like this under my car (2 different liquids leaking), I'll get it fixed. Even if my car has more dents per sq. meter.

One more reason to install a nose wheel pant -- it keeps fuel and lube leaks from rotting your front tire.

Oil leaks aren't too big a deal, unless something is obviously coming apart.  My O-290 oozes oil all over the place, mostly out the cylinder studs and flanges.  Not worth fixing.

Welcome to Aviation.SE! I rejected your edit request for one of the answers below because it's better to include relevant information / pictures in your question rather than adding it to an answer. Feel free to add the image here.

Not qualified as a mechanic but wish to share a story about a failing intake valve spring allowing fuel/oil to be pushed all the way back to the air filter (in a one cylinder 4 cycle generator).  Loss of rpms is concerning.  If you know for sure it's not due to higher air density, checking the valve springs (one may be broken) might not be a bad idea.

Oh man, really? A fuel leak is nothing to be concerned about? After all fuel is the thing that burns inside the engine, and it being outside the engine is bad, be it before, during or after the flight as it will also quite happily burn there too.

"My aircraft engine has a fuel leak.  Do I need to fix it right away?"  Yes, and I truly mean this in only the kindest way, you really need more training & education since you have to ask.  I mean, I'm glad you're asking, but at least to me, the answer is obvious.  If another A&P finds a problem, submit their report to the licensing board and get that original A&P's license reviewed.

The drips only after shutting down means fuel is coming from somewhere it shouldn't and is being pulled into the engine while it's running, and when there is no intake flow, the fuel dribbles out the other direction until the level of fuel at the source drops below the leak point.  This is supported by the low static RPM, that suggests an over-rich mixture.  You should look for soot on the exhaust pipe and sooty spark plugs.
There are a number of potential issues with Marvel Schebler MA series carbs.  One well known one is foam or brass carburetor floats that start to sink, causing the regulated fuel level in the float bowl to be too high and which tends to flood the engine.  When the engine is shut down, the fuel in the bowl may leak out until the level drops below the metering outlet.  If the carb float loses all its buoyancy, the engine will flood out and will probably quit on you, so that is something that needs to be addressed.
It's a great idea to get a second opinion.  Fuel dribbles after shut-down, with signs of an over-rich mixture, are not normal. Besides the operational problems of the engine itself, fuel collecting into air boxes is a significant fire risk.
It'll probably be easiest just to replace the carb at the annual. An overhauled MA-3 and 4 carb typically used on Lyc O-320s and Cont O-300s costs about 800 to 1000 dollars plus installation.
Here is a link to Marvel Schebler Service Bulletins, where you can learn the various issues with those carbs:
https://msacarbs.com/technical-data/service-bulletins/

Thank you for the link.....I'm definitely getting it to a different mechanic and having the annual started 2 months early

If you're mechanically inclined, find a guy who will let you do the grunt work under supervision.  Nothing like getting to know your machine intimately.

I'd take it to a different A&P as this is definitely cause to be concerned. A 150rpm power loss could be cause by many things: tuning, bad spark, fuel pressure, etc. But, leaking fuel is not normal and there's a brown stain that looks like it could be oil, in which case you have real problems. It could (hopefully!) be something simple and cheap or you could be looking at an overhaul, but you should get it looked at.

I don't generally work with airplanes, but I have seen this on a lot of engines when the carburetor gaskets and/or float valve starts to have various issues.  As long as the leak stays small it is unlikely to cause an immediate failure to run.
Eventually, as it gets worse, you'll probably find the engine starting to flood out and stop when not at full throttle.
One way to mitigate the leakage until you can get it fixed may be to turn off the engine by shutting off the fuel rather than by turning off the spark.  This will empty the carburetor bowl so hopefully the remaining fuel in the lines won't drip quite as much.  (This is also slightly better for a gasoline engine in most cases anyway as it reduces the cylinder wash from unburned gasoline going through the system as the engine spins to a stop.  Engines which mix the oil into the fuel being the one exception.)
I would, however, recommend getting it fixed as soon as you can.  If nothing else, it's wrecking your paint job and is a fairly substantial fire hazard.

A carb overhaul should fix the problem. Your float could be set at the wrong height, sticking. Your needle and seat could be leaking and not maintaining the proper fuel level in the bowl of the carburetor. You could have varnish if a plane has been sitting for some time on the tip of the needle, making the valve not closing properly thus flooding the engine and causing you loss of power.

Alright, fuel dripping down and staining your wheel pant is definitely something to address. Engine RPM may differ due to temperature, density altitude, and that Tachometer is not the most accurate thing in the world to begin with. The Tpe Certificate Data Sheet says your prop (Assuming you have a O-300 and a McCauley 1C172/EM 7652, 53 prop) states that the engine during a static run should be no less than 2230 and no more than 2420. You are within the range.
Let's really focused on the fuel leak. Where is the fuel coming from? Around the fuel fittings going into the carb? Around the seal between the upper and lower sections of the carb? Is it coming from the throat of the carb? If you can't easily tell, spray the carb down with some paint thinner or alcohol. Just something that will evaporate and clean the old fuel off. Then see where your leak is from. Systematic troubleshooting will save you money.
Cessna 172E owner/A+P/IA

I’m an A/P. I agree, you probably need a carb overhaul. Your mechanic should be able to do this for you. If you have an older carb, with a two-piece Venturi you may want to exchange yours for a new or overhauled unit. It would have a new-style float, and a one-piece Venturi That would get rid of the ADs against your carb.
I agree with the others that recommend cutting off the fuel supply with the fuel selector. This checks to make sure that it is still functioning 100%, and you can be sure to stop the fuel flow in an emergency. Everyone should perform this check once per week if you fly a lot, or every time you fly if you fly less often. Just my opinion. It is checked on every annual and 100hr, but it won’t hurt to check it more often. Some fuel selectors barely move because people leave them in “both” at all times.

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Why five touchdown zone markings for only one aiming point?
RWY 24 at Paris-Orly is a runway sustaining precision approaches. There is an aiming point and five touchdown zone markings.

Orly RWY 24, source: Google Maps
Aiming the visual aiming point, or following the ILS/PAPI glideslope should bring the aircraft on the runway before the aiming point.
Why five touchdown zone markings, in particular the three after the aiming point?
Related, but not duplicates:

What are runway Aiming Point markers used for?
What determines the touchdown zone and aiming point markings on a runway?

From the answer: "Touchdown zone marking" doesn't refer to a marking that would indicate a touchdown zone, which would imply multiple touchdown zones. Instead it refers to all markings in the single touchdown zone, including the aiming point markings.

I find these EASA or ICAO markings intriguing. The location differs from the FAA markings that I am used to. I am used to seeing the aiming point bars located at 300 m. Here they are at 400 m.

ICAO Annex 14 specifies the need for 6 pairs of touchdown zone markings for runways with a landing distance available of 2400 metres or more.

As noted in Annex 14, the number of markings relates to the landing distance available.
Presumably, the rule is there to make it easy for a pilot approaching the runway to make sure the runway is long enough if, for some reason, they are uncertain of the runway length. Similar logic could probably be applied to the rule regarding threshold markings ("piano keys"): What does the number of white bars in runway's threshold mean?

For instance, if an airport has two (or more) parallel runways of considerably different lengths, and a pilot is shooting a C2 ILS approach through the fog, they'd be able to tell by the number of bars whether they were following the ILS for the correct runway, or whether they'd, instead, inadvertently locked onto the one next to it.


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Can an aircraft continue flying and land safely following an engine failure?
Is it possible that an aircraft could continue to fly and then land safely on a single engine if another stopped working?

The answer to your question strongly depends on what kind of airplane you're talking about (in particular, what set of rules it was certificated under), as well as the phase of flight you are in (takeoff vs. cruise vs. approach/landing) and whether you are in a jet or a (turbine or piston) propeller aircraft.  (I'm going to exclude single-engine airplanes from this discussion, as well.)
Cruise Flight
In general, an engine failure in cruise flight is a manageable emergency unless you are in extremely high terrain in a light twin or some other corner case.  The general procedure is to "drift down" in a slow-ish descent to your single-engine cruise altitude -- if you don't already have a driftdown airspeed worked out, you can use Vyse as a substitute to get a slow driftdown -- and then divert to a nearby suitable airport to get the busted engine looked at, as you'll be flying lower and less fuel-efficiently as a result.
Takeoff
Takeoff is the most troublesome time for an engine failure to happen, bar none: you are at high gross weight and don't have altitude under you to turn into airspeed and landing options.  What you want to do is get to the pattern altitude, fly a pattern, and land in a reasonably quick, but orderly fashion -- you don't need to ultra-hurry things even if you have an engine on fire, but you do want to get back on the ground in a reasonable timeframe to get things looked at.
Light Twins (cabin class, commuter, pre-FAR 25 airliners)
These aircraft, unfortunately, struggle in single-engine situations on the best of days, as the certification requirements for single-engine performance in FAR 23 are minimal at best.  The common adage you will hear about light twins, even, is "the second engine will carry you to the scene of the crash" -- it is possible for a light twin to be type certificated with nil or negative worst case single-engine climb performance in the case of an engine failure at or shortly after takeoff.
Business Jets (certificated under FAR 23)
Corporate or business-type light jet aircraft (Citations, Gulfstreams, LearJets, Beechjets, etal) and their turboprop counterparts (such as KingAirs), while often certificated under Part 23, will generally have superior single-engine performance to light twins, although this is by no means guaranteed.  You'll likely get up into the pattern and be able to make a reasonably normal single-engine landing, barring any aggravating factors at least; this is because even the smallest turbine engines are large enough that the aircraft will have some degree of excess thrust as a twin, leaving it with a thrust reserve in a single engine situation.  These aircraft are also flown by pilots with type ratings and a CPL or ATPL, which means they will be more familiar with the performance of that specific aircraft and any aircraft-specific engine-out procedures needed to eke out maximum single-engine climb rates.
Twin-Engine Airliners (transport class twin turboprops and twin jets certified under FAR 25)
The FAR 25 requirements for engine-out takeoff performance are much more stringent than FAR 23, and practically guarantee that the aircraft is capable of positive climb in a V1 cut (engine failure right after decision speed) at maximum takeoff weight.  In addition, V1 cuts are a classic airline training scenario that every airline flight crew on the planet runs in the sim on a regular basis (I wouldn't be surprised if a V1 cut came up every few sim sessions or so, if not every sim session).
In a practical sense, this means that unless the aircraft is overloaded or is suffering from something beyond a simple engine failure (I'll talk about that later), an airline flight crew will handle engine failure on takeoff in an airliner as a routine event.
3 and 4 engine airliners
A single engine failure on a three or four engine aircraft is by no means critical, especially on three- and four-engined jet transports.  This doesn't mean that 747 crews don't practice V1 cuts any longer, though!
Props vs Jets
Engine failure in a jet, whether it be a T-37 or an A380, is simple: you put appropriate rudder in, ID which engine died (between your instruments and "dead foot, dead engine", you should have enough data to go on), add power as needed on the working engine (say, if you are doing an assumed/FLEX temp takeoff), and kill the dead engine, then run the rest of the checklist at a leisurely pace now that safe flight is more-or-less assured.
Propeller aircraft are a bit more complicated though in that you need to feather the dead engine's propeller to keep it from dragging the airplane down -- older constant-speed prop designs such as those on warbirds and piston-engine airliners had FEATHER buttons for this job, one per engine; newer aircraft with constant-speed props have a gate on either the power or the condition levers that serves in place of the feathering button.  You also have more levers to manipulate when adding power to the working engine(s) and killing the dead engine, and may have more difficulty figuring out which engine died without positive flight control responses (I can only imagine how baffling a center engine failure on a Trislander would be!).
As a result of the critical nature of the feathering process, modern (and even some not-so-modern) transport-class (and some other) propeller aircraft have an autofeather or NTS (Negative Torque Sensing) system that will automatically drive the blades of a propeller towards (or even all the way to) the feathered position if it is armed and senses that the propeller is trying to drive the engine.  However, feathering the propeller on an engine that isn't shut down is also a bad idea as it causes the propeller and engine to overspeed due to the airloads the engine was driving going away.
Of course, if you are in a light twin with fixed-pitch propellers, none of this feathering talk applies.  Be prepared for the unexpected emission of foul language during engine-out procedures, though!
Approach/Landing
An engine failure during the early phases of approach is generally unproblematic -- it's similar to a failure at cruise, just minus the driftdown.  However, an engine failure on short final can be troublesome due to the high workload of an approach, combined with the thrust asymmetry induced during a full-power, single-engine go-around.  Prompt rudder inputs are essential in order to maintain aircraft track and control during such a maneuver, and engine failure checklists are best deferred until stable flight.
Engine failures during the landing roll are rare, by the way, and typically a non-event.
Worse than Engine Failure
There are engine damage scenarios that represent a greater hazard to the aircraft than a simple engine failure, or even a fire in an airliner engine.  These fall into three categories: uncontained turbine engine failures, engine detachments, and propeller failures.
Uncontained Turbine Engine Failure
Turbine engine failures are divided into two types: "contained" failures where the busted parts fly out the tailpipe, and "uncontained" failures where a turbine or compressor disk basically explodes radially, sending parts flying in a 360° radius around the engine; at this point, further damage is a game of aerial roulette, and can range from a few holes in the cowl to near-catastrophic levels of damage that pose a threat to the entire aircraft.
Engine Detachment
Engines, even when pod-mounted, rarely fall off airplanes, and much of the time when they do, they depart quietly, a yanked-back thrust lever and nil engine readings the only signs of their absence visible to the flight crew.  However, a detached engine is somewhat unpredictable in its behavior, and can strike another engine on the same wing or another part of the aircraft, leading to further damage that can compromise aircraft systems or impair the operation of that neighboring engine to the point where the thrust asymmetry becomes uncontrollable.  Nacelle-mounted engines are actually worse in this regard -- a nacelle-mounted engine departing its nacelle leaves behind a big, draggy air scoop that will severely hamper single-engine flying, and on a light twin, this is simply insult atop injury as you have gone from "barely making it to your site of choice" to "we need to pick the nearest open spot NOW because we're trying to fall out of the sky in a hurry"
Propeller failure
Propellers do not fail nearly as often as engines do, but when a propeller fails in flight, the results can be catastrophic; an overspeeding prop can fly apart violently or rip its mated engine apart while producing asymmetric forces that have the potential to overwhelm all flight control, while the inability to feather a failed engine's propeller turns it into a drag brake on that side of the aircraft, crippling any attempt to obtain reasonable single-engine climb performance.

Do you have an example occurrence where the engine detached without further incidents?

There have been several, but JAL Cargo flight 46E is the most-investigated of them.

Regarding propellor failures, this video of a propellor departing the engine during a flat spin at an air display is very impressive. It shows that exceeding the lateral stresses on driveshafts can have catastrophic consequences, but that even in a single-engine aircraft at an unusual attitude with low airspeed and altitude, a (very) skilled pilot can recover from an engine failure.

Yes. All two-engine (and three- and four-engine) aircraft are certified to safely land if one engine fails at any point on the route, including even the most critical parts of take-off.
However, lower engine performance will force a reduced service ceiling. Basically, the plane will have to fly lower, and less efficiently, so often it wouldn't be able to get to its intended destination and instead would have to abort to a nearby airport.

This is a bit rosier than it should be -- light twins have an abysmal record WRT engine failures, unfortunately.

@UnrecognizedFallingObject sorry, I haven't seen those figures.

Not all, only transport category, which means 12 or more passengers (FAR25 in FAA regulations; there is corresponding regulation in other parts of the world).

Short answer is yes, and the immediate challenge is correcting for the unbalanced thrust from the remaining engine. It is certainly a disconcerting feeling flying on one engine when you are used to 2. Kind of like a high wire act without a net.
Sharing a bit of humor here. I flew the A7E a single seat, single engine, light attack jet for the US Navy. We never liked declaring emergencies, and would often use euphemistic language in our communications over such small affairs as engine troubles. I heard this story a while back and thought it apropos to the question.

A military pilot called for a priority landing because his single-engine jet fighter was running "a bit peaked." Air Traffic Control told the fighter pilot that he was number two, behind a B-52 that had one engine shut down. "Ah," the fighter pilot remarked, "The dreaded seven-engine approach."


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In the upper air, do pilots use flaps to generate lift as well slow down an aircraft?
I know, flaps are mostly used during take-off or landing to generate both lift and drag simultaneously.
I am wondering if the pilot uses flaps to generate more lift so that they can climb in less distance (due to drag of flap) and possible reasons for doing it. I have an idea that the flight control system may prohibit flap deployment above a certain altitude or at higher speeds due to flap structural limitations.

It's a little complex, but here is a shot. Take a look at the following graph:
graph http://www.navlog.net/wp-content/uploads/2012/10/PowerAvailable.png
What you can see is multiple airspeeds. For a plane, the rate of cruise is maximised around Airspeed B is reached- this is when the difference between power available and power required is the greatest and therefore the most excess energy is available for climb.
The slope here indicates how much power is necessary for that airspeed- the steeper the curve, the worse it is. The value is really high for airspeeds all the way to left.
If you were to deploy the flaps, you would sort-of shift the power required curve to left- adding drag, reducing the difference between the power available and power required, reducing the maximum rate and in the process increasing the power necessary.

(source: ppl-flight-training.com)
In the equation above, you want to increase lift. Yes, you can do this with flaps- it would increase CL. As you yourself state, it takes a lot of drag to use flaps and slats. Another option is to increase velocity. This is more efficient and uses less energy.
The reason we need is flaps is since as the velocity drops for landing, we need to increase the CL to maintain sufficient lift for landing. Airspeed for B for landing though is much too fast, so you want to slow down to the left side of the graph. See this post on a little more detail on this relationship.
As for flap limitations, they appear to be 20,000 ft for the Boeing 737- Mostly because boeing found them unnecessary to use at higher altitude.

Perfect technical explanation for use of flaps and got very good understanding of it.
Consider if pilot see another aircraft on same altitude approaching towards it, now pilot thinks to change altitude in such a way that he covers less distance (forward speed should be less) but more climb. Is use of flap in this case solves the problem or there are other ways

@ToUsIf if a pilot sees another aircraft approaching it, he will not use flaps to rectify it; that's most definitely not an expedient way to move. General procedure is to climb (quickly! pull back the yoke/stick) and turn right. This procedure allows both pilots to make the same correction at the same time, or a single pilot to take the action, and neither possibility leads to a more likelihood of in-air collision.

That's actually what modern TCAS are doing, coordinating such maneuvers between airplanes. The system will tell one pilot to climb and the other pilot to descend (TCAS II). For the newer TCAS III, horizontal maneuvers are also expected.

@ToUsIf: Extending flaps will not make the aircraft climb faster under any concievable or other conditions. The aircraft does not need more lift to climb (except briefly to initiate it). In steady climb, the lift only needs to balance weight and that is still the same. It however needs energy and energy is lost by drag, so extended flaps is the last thing you may need.

@ToUsIf: Also note the v² in the above equation for lift. It means that at higher speed the aircraft has plenty of lift available.

Graph link seems broken.

Most planes have a flap extension (Vfe) speed limit. Deploying them at cruise speeds will damage something. Even small planes have a limit, example for a 172:
VFE Maximum Flap
Extended Speed:   KCAS  KIAS       Do not exceed this
10°         Flaps 107   110        speed with flaps
10° to 30°  Flaps 85    85         down.
One may have trouble getting the plane to go that fast with the flaps down, but once they are retracted and speed increases, deploying the flaps above those speeds may damage something.


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What is the mechanism by which condensation forms above wings?
The planes landing at Sydney Airport have what looks to be sheets of steam pouring off the wings. Larger planes have multiple contrails while smaller regional planes only have these sheets.
This is the first sunny day after a large storm. There are patches of dark cloud.
From the link posted by fooot, I've learned that it's condensation, but what is the mechanism by which it forms?  The video shows planes in poor weather, but visibility here is excellent, with 20% cloud coverage.

Like this?

In a foggy weather relative humidity is always 100%, so the effect occurs. But if the ground is soaked wet, the water will be evaporating at just the rate the air can take it, so the humidity will also be very close to 100% without any visible fog and the effect will appear too.

We know that the pressure decreases over the wing. We can also assume that a particle of air travelling above a wing does it  so fast that does not have the time to exchange energy with the sorrounding ones (called adiabatic process)
We can now look at a pressure/volume diagram for an adiabatic process that goes from "high" pressure (the free undisturbed air in front of the aircraft) to low pressure (the air on top of the wing):

image source (currently unreachable)
As you see from the diagram, if you move along the Adiabat line from the top to the bottom, the temperature drops. If the air has already a temperature near the water condensation one and a high enough humidity, it will condense.
From the Wikipedia article linked before:

Adiabatic cooling occurs when the pressure on an adiabatically isolated system is decreased, allowing it to expand, thus causing it to do work on its surroundings. When the pressure applied on a parcel of air is reduced, the air in the parcel is allowed to expand; as the volume increases, the temperature falls as internal energy decreases.

I actually can't see that. I only see pressure and volume on the graph

@raptortech97 the 2 red lines Isotherm (meaning "same temperature") are 2 lines where, moving along them, the gas does not change temperature. The Th (Temperature high) has higher temperature than the Tl (Temperature low), as pointed out from the Th>Tl remark. Moving from one red line to the other you change temperature.

That makes sense. Wouldn't it be easier to derive this from the ideal gas law, tho?

@raptortech97 you can, and it is done in the wiki article. I wanted to keep the answer equation-free.

An important concept here is dew point. The dew point temperature is related to the current temperature and the humidity of the air. For example, near sea level, a temperature of 51°F and humidity of 86% gives a dew point of 47°F. If air is cooled below the dew point, the water in the air will condense. You can see this effect on a cold glass; the air near the glass is cooled below the dew point, so the water in the air condenses onto the glass.
When humidity is high, the dew point is very close to the air temperature, which is why it's easier to get condensation when the humidity is high. When the air temperature cools down to meet the dew point, fog forms. The water vapor in the air is condensing, but without a surface to gather on, it condenses into small droplets that form fog. Humidity will be high in foggy conditions, and often when it is raining, but can also be high in other circumstances. Jan Hudec's comment notes that as water is evaporating from the wet ground, there can also be high humidity.
Federico's answer does a good job of including the gas physics at work on the airplane wing. The important link is that as the wings create a low-pressure area, the temperature falls along with the pressure. If the dew point is high enough, this temperature drop may only need to be a few degrees. The water vapor condenses in the air, with the effect that you noticed. Once the air has passed over the wing, the pressure eventually returns to normal, along with the temperature, causing the water to evaporate again.
The small "contrails" that form are from a similar effect. At locations such as the edges of flaps, a vortex is formed. This is a section of tightly spinning air. Similar to the wings, the acceleration of the air lowers its temperature and pressure, causing the condensation to form in the air. The vortex will eventually dissipate, and the condensation evaporates.
Actual contrails that form behind planes at high altitudes are due to a similar but different effect, and there are some questions here discussing them.

Federico's answer nails exactly what's going on, although for us Poetry majors, the graph can look confusing.  Let me add this simplified explanation, plus address something that showed up briefly in a now-deleted answer.
In short, condensation happens with cooling.  We see liquid condense on the side of a cold glass of liquid on a hot day, and happens when air "here" (near the glass) is cooled below the dewpoint, so the humidity condenses into water drops on the glass.
When you see clouds/condensation/vapor trails forming above or directly behind the wing of an aircraft landing in humid conditions, the same basic phenomenon is taking place, but instead of condensing ONTO a surface, the condensation takes the form of a "cloud" or "vapor trail" streaming behind the wing.  Here, the cooling is caused by the air: with the air above the wing having lower pressure, it has cooled (PV=NRT, vaguely remembered from physics, Pressure goes down, so does Temperature), and when the air is humid enough with the spread between temperature and dewpoint very close, that cooling is enough to give you the condensation.
A similar but distinct phenomena that causes condensation ON the wings, but not BEHIND them, is cold-soaked fuel.  When an aircraft has been flying at high altitude for a long time, where the temperatures are far below freezing (-40 degrees or so), the fuel inside the tanks in the wing gets cooled to similar temperatures.  On the ground, this fuel acts like the liquid in the glass, and you get condensation on the wings, and frequently, "cold soaked fuel frost" that forms after the condensation freezes onto the surface of the wing.
This is NOT what causes the vapor trails observed in the original question, because there isn't enough time for the rushing air to be cooled by the cold wing.  THAT happens due to the change in air pressure.  Parked, you don't have the lift/low pressure, so that cooling mechanism is gone, but with stationary air, you have the other effect at work.


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Is there a way to get the original data used to create performance charts?
I want to create a flight planning software for GA. Just as a prototype for the time being. The performance data and info about the planes should be stored in various databases.
When I go through flight manuals like the CESSNA 150, I get a lot of tables which I could convert into a database, but where do I get data which created these charts e.g. the range profiles?
Is this data available somewhere? Or are there databases available to be used?

I think you may be under the impression that these charts were computer generated, when in reality they were done with pencil, paper, and slide rules back in the 60's and 70's. This data may be available electronically for newer aircraft (post 80's or 90's), but you would have to contact the manufacturer for each individual aircraft. You are probably better off trying to find out how they calculated the curves instead of just digitizing graphs.

I did not think about that.... you are right. But how are tools online calculate the endurance/performance for a specific flight plan entered by the user then?

@RonBeyer Many of the charts are created from flight testing, with data points from actual observed data (not calculations from a formula), or a combination of observed data and extrapolated data.  I believe that software providers digitize the actual graphs and use the data "from the AFM" to perform their calculations.

Hm.. digitizing the graphs.. I think that can be a challenge.

@Lnafziger Yes, no doubt about that, what I'm saying is that the aircraft back then didn't have sophisticated recording devices that provided terabytes of data on performance, it was probably a guy shouting out data points while somebody copied them down, later connected via manual drafting and filling in the gaps with interpolation and extrapolation.

As others have stated, the data certainly exists but the manufacturers are under no obligation to provide anything more than what's in the manual.
That said, the performance equations are straightforward and with some effort you could build the tables.  What you are proposing exists for most air transport aircraft for their Flight Management Systems.
As a reference, you might check out Getting to Grips with Aircraft Performance.  It's written by Airbus but provides a very good explanation including much of the math.

I have never seen a digital copy of this data but that does not mean it does not exist. However you should note that strictly speaking this data is unique to every air frame from a legal standpoint. According to FAR §23.1581 every aircraft must come with this documentation and once issued the documentation is specific to the air frame (not the general type). Generally speaking these pages are never changed (only the W&B ever practically changes). Things like performance charts may also change depending on the engine installed in a given air frame or other modifications made. The data could be valid in a general sense but not in the specific sense. There are digital apps out there for things like W&B (which foreflight now includes) but generally require you to enter the specific information for your given aircraft.

I agree, it is individual per plane.. but how do apps like foreflight work or others? Of course you have individual data to be entered, but all the information about performance, endurance etc. How is this being used for calculations within the software? YOu don't enter this dat manually, right?

All of this data is entered manually per aircraft in Foreflight when you set up a new plane. You can check out Page 192 of the instruction manual for details.


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What are the minimum requirements to pass the FAA medical exam?
What are the requirements like height, weight, sight to pass the medical exam for getting a pilot's license ?
Are there any medical conditions that would make someone to fail it?
I know daltonism would be one of those.

Related

Many medical conditions make you fail the FAA medical exam. If there weren't such conditions, they wouldn't have the medical exam,

In the US there are three classes of medical, each with more stringent requirements so you need to specify what kind of flying you intend to do.

There are no height or weight requirements as far as I know and you dont need perfect vision. I wear glasses and have a "corrective lens" note on my medical. I think that at minimum your vision needs to be correctable to 20/20. See this link for some information as well as the information for doctors here. You can also get special dispensation for certain medical conditions.
On a small side note, if you are asking this in relation to a Private Pilot License, they may be doing away with the current third class medical regulations which will ease the regulations greatly.

All specific requirements to obtain a U.S. FAA Medical Certificate are listed in Part §67 of Title 14 of the Federal Aviation Regulations (FARs).

§67.1 Applicability:
This part prescribes the medical standards and certification
  procedures for issuing medical certificates for airmen and for
  remaining eligible for a medical certificate.

It lists all specifications that have to do with the eye, ear, nose, throat, and equilibrium, mental, neurologic, cardiovascular, general medical condition and also any discretionary issuance.
To answer your specific question, you don't have to have a minimum/maximum height-weight to obtain a medical certificate. The operation you conduct and the company you conduct it with may have certain height-weight requirements.


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How are helicopter cyclic and collective jacks connected?
Regardless of the degree of collective pitch applied, the cyclic pitch controls must retain their full range. Both controls are via jacks, so how are the jacks connected?

Have a look at this related question and answers.  The jacks connect to the fixed bottom part of the swash plate.  Moving the swash plate up and down (collective pitch) has no effect on how much it can tilt (cyclic pitch)

Perhaps I should elaborate on my question. Movement of the collective jacks will push or pull the swashplate which will pull or push the cyclic jacks. So how are all the jacks connected at their lower ends?

You may want to edit your question, rather than have the clarification in a comment, and state by "jacks", are you only interested in heads controlled by hydraulic jacks or also by push rods? If you really are interested in jacks, then I don't understand your question since the lower end of the jacks are fixed.

This may help

What model of helicopter are you referring to?

The helicopter Collective and Cyclic controls are connected to the rotor bladesby swash-plates. The following is a swash-plate :

The following animation shows the connection assembly working :
Swash plate in the resting position.

A raised swash plate causing negative collective blade pitch and thus down force. Note that the control arms are on the trailing sides of the blades, causing raised swash plate to decrease the blade pitch.

A tilted swashplate giving cyclic blade control. Note the change in pitch of the blades during rotation.

Source : Wikipedia

That rotor head looks suspiciously like a model helicopter.  RC helicopter heads are quite different to real ones.  Your answer also does not address the question.

Wikipedia reference

I know how a swashplate works. It's the bottom end of the jacks (or actuators - same thing)  that I am asking a question about.

Ah, yes, it is a model helicopter.  Compare it to real ones.  There are significant differences since the constraints of weight and strength are largely removed and full articulation is the goal.  Model helicopters can do things a real helicopter can only dream of ;)

There are three "jacks" providing both collective and cyclic movement to the swash plate, the difference is in how many are moving.

All three are used for collective input: they all move, so the swash plate goes up/down
For longitudinal and lateral movement, only one (or two) depending on configuration) are deflected, so the swash plate cants.


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How is the pitot/static system of a helicopter affected by rotor downwash?
Since the fuselage of a helicopter is affected by downwash from the rotors, how is the pitot static system affected?

The pitot tube is not much of a problem - it's your typical pitot tube, pointing forward (toward the nose of the helicopter) to measure forward airspeed. Airspeed is somewhat less important to a helicopter pilot than it is to a fixed wing pilot since lift is generated by swinging the rotor around instead of moving the whole vehicle through the air.
The static port requires a little more thought, because it should be located in an area of "undisturbed air", and being in rotor wash is certainly not "undisturbed".
On the R22 the static port is actually located inside the shell per the maintenance manual and is thus shielded from rotor wash:

You could locate the static source in a similar unpressurized-but-shielded compartment in a pressurized helicopter.
On other helicopters the static port is on the fuselage as on most aircraft, for example this one is on an HH-2D Seasprite:

Note that the static port is slightly recessed on the seasprite to keep it out of direct rotor wash.  Multiple static ports may also be used (again, as you'll find on other aircraft) to give an average static pressure and reduce the effects of rotor wash on the static pressure reading.
As with all static systems there will still be some degree of error - no system is measuring truly static air. As long as it's within a reasonable tolerance all the instruments should be able to be calibrated to read correctly though.

To keep matters short I will post below the IAS-CAS graph for an EC 135 helicopter.
As you can see the differences are really small for almost all the speed range. At very low speeds and in hover there may be bigger errors, but in those situations you are not looking at airspeed indicator or altimeter, you are looking outside.


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Does Part 135 duty time begin at the start of a part 91 owner flight which occurred immediately before?
You are asked to fly a 91 owner trip to a destination. A 135 trip comes up after your owner flight.
Does your 135 duty time start when company asked you to fly the 91 owner flight?

Absolutely, 135.267 (d) requires you to have 10 hours of rest within the 24 hour period preceding the completion of every 135 flight, and if the 91 flight is for the same company then it is not considered rest. Duty time starts when you are required to do anything for the company, and for a typical flight it starts when you arrive at the airport.
For more information on rest, see this question and answer.


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Can a piece of duct tape bring down a plane today (Flight 603, 1996, Perú)?
According to Wikipedia, the reason for the crash was that:
adhesive tape had been accidentally left over some or all of the static ports (on the underside of the fuselage) after the aircraft was cleaned and polished
Can this still happen with modern aircraft?

Mentour pilot has an accident reconstruction based on NTSB (or equivalent agency) findings for Malaysian Airlines Flight 134, which took off with pitot tubes covered whre he does a pretty nice explanation of the whole system for laymen - https://www.youtube.com/watch?v=f80WwpNuaxg (the titles and intros are a bit over the top, but the content is top notch) - it is not precisely about static ports, but very related.

OP, one way to understand this: the duct tape was literally covering the EYES (!!!!!) of the robot that is the overall aircraft.  The aircraft had utterly no clue WTF was going on; most of its senses had been blindfolded.

Yes, this can happen on all aircraft.
The static ports on the aircraft were covered with tape for cleaning, and then not removed. This resulted in contradictory flight data (mainly airspeed and altitude) being fed to the pilots, including that relayed from ATC. Similar actions in modern aircraft would have a similar effect. More modern aircraft have specially designed covers that are used instead of tape, making it less likely they will be left on.
In theory the presence of a measure of speed that did not rely on pressure sensors (such as INS or GPS) might provide some degree of protection, as might an altitude measure that did not rely on the plane's sensors, but it is not guaranteed even with those that the pilots could have figured out how to get reliable airspeed or altitude figures in the circumstances.

Though even the 757 in the accident had radar altimeter, the crew didn't know which instrument to trust. I agree that even with GPS it would take some fast thinking on part of the pilots to figure out the situation. Fortunately modern maintenance procedures use bright-colored protective caps instead of pieces of tape :)

@jpa The maintenance procedures at the time required bright coloured tape. It just wasn't used. The maintenance worker responsible was found guilty of negligent homicide.

The risk has been mitigated, but the potential will always remain... consider the "Swiss Cheese Model".
If:

The cleaning crew working on the aircraft "bent the rules" and chose to use duct tape perhaps because the proper covers were not readily available, with the reasoning that the worker who applied it will remember to remove it before returning the aircraft to service.

There is a shift change before the work is completed, so the incoming crew is unaware of the duct tape and does not need to do any work in the affected area of the aircraft.

The aircraft is returned to service after nightfall and there is poor lighting where it is parked; the flight crew happens to be running late and so is in a rush to complete the pre-flight.

Then, there will be a repeat of the thing that should never happen again.
At each step, there is an opportunity to prevent or catch and correct an issue so it won't propagate, and only small things at each step can make the difference between non-event and disaster.

I'd perhaps make this a comment but it's too long.
This is a "hopefully) useful addition to the other answers.
This is an example of Anthony X's "Swiss Cheese Model".
A large proportion of major disasters require 3 to 5 "impossible" things to happen to allow them to occur. (Sometimes just bizarre, unusual or wholly unexpected).
A classic example is the Air NZ Flight TE901" loss of a DC10 on Mt Erebus in Antarctica
(on Novermber 28, 1979).

The original route WAS over the mountain.
A transposition error in data entry took all flights up McMurdo Sound
so this became the "known route".
On the day before the flight someone did a routine course recalculation and noted an insignificant error.
They entered the updated data - maybe moving the course a tiny fraction of a degree off where it "should have been".
But, this change overwrote the original transposition error and put the aircraft back over, and so into, the mountain.
There was a "whiteout" (this is Antarctica!)
And the captain assumed the course was low-level safe, as it always had been previously.
It wasn't.


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Has someone with no experience at all ever taken off in a plane? Could they?
I was watching Mystery Science Theater 3000 and their showing of 1970 TV movie/pilot San Fransisco International.  One of the plots in the movie involves a twelve (or so) year old boy, who, alarmed about his parents' imminent separation, wanders across the tarmac, hops into the cockpit of an Aircoupe, and flees his mother by starting the plane and taking off before anyone quite knows what's happening.  After he unsteadily flies it a bit (the best part of the movie is some stunt pilot making the Aircoupe swerve through the air like a drunken eagle), Bonanza's Adam Cartwright talks him through a safe landing.
Plenty of questions have been asked about the possibility of planes being landed by someone with no experience at all, and, of course, talk-down landings are a real thing, even if they're rarely done by anyone with zero experience.  But I'm curious about the first part, where the kid turns a key, taxis away, and is up into the California sky without even having played Microsoft Flight Simulator.
Naturally, a civilian getting into a cockpit at SFO without being stopped seems patently absurd in the security-conscious present, but times have changed.  Has anything even similar to this ever happened?  And if not (if this doesn't over-broaden my question) could a layman get a plane, single-engine or otherwise, into the air without any experience?

Are you talking about anybody who doesn't have a pilot certificate (may be self-taught, for example), or are you talking specifically about somebody who does not have any flight experience, even simulated?

See also Colton Harris Moore for more stories.

As suggested by an answer- "amateur" is not really the right word or phrase-- substitute "complete beginner" or similar-- elsewhere you used "layman".  PS it's worth noting that the Aircoupe is designed to be a VERY forgiving aircraft.

@quiet flyer: Yes, most pilots - basically everyone who doesn't hold a commercial or ATP license - are by definition amateurs.  I certainly am :-)

umm, Orville and Wilbur?

Any trainee doing their first take-off?

There's a suggested element of "accidental takeoff" implicit in the question.  Do you intend to include or exclude intent in this question ?

Guys what's with the "edit fear"  :)  If you see a question with an obvious typo or obviously an incorrect word, just click edit.  (If surprisingly your fix is wrong, the OP can re-fix.)

Were either of his parents pilots? Is it possible he saw them fly and figured it out that way? That'd be a bit different than no experience whatsoever.

@Fattie: Not fear, good manners :-)

It should be mentioned that taking off is the easy part.  Planes have been known to do that without anyone at the controls, e.g. https://www.chicagotribune.com/news/ct-xpm-1997-11-24-9711240036-story.html  Landing again is the hard part :-)

fasctinating, @jamesqf !

@mcalex I thought the Wrights practiced with unpowered flight before they attempted a powered takeoff.

A guy took off at Tacoma just a couple of years back, and although he had plenty of time in the simulator, never flown anything in his life. Handled it very well till he started aerobatics with the huge Canadair commuter. Eventually crashed into Puget Sound.

The Aviation Safety Network has an article listing 11 airplanes that crashed after being stolen by a non-pilot. The most recent was the Horizon Air Dash 8 that was stolen by a ground service agent in August 2018.
There are more interesting stories such as:

The guy that tried to crash a Cessna 150 into the White House (with minimal experience and training)
Ground crew member that stole and crashed an F-16 in Norway
Mechanic that accidentally took off in an English Electric Lightning
Mechanic that took off in an F-86 Sabre
15-year-old that stole a PA-34 and took off with 4 passengers, later crashing

Whether these qualify as "amateurs" is a matter of opinion. Most of them were mechanics/engineers. It would be difficult (but not impossible) for a person not familiar at all with the aircraft to get it started and manage to take off.

The "Barefoot Bandit" (aka Colton Moore) stole at least 2 aircraft without any formal training.

And there’s also this Marine who had what can only be described as a great Independence Day and stole an A-4 jet from MCAS El Toro and took it for a joyride.  He landed it safely and faced a fate similar the the F-86 mechanic.

https://foxtrotalpha.jalopnik.com/the-tale-of-when-a-marine-mechanic-stole-an-a-4-skyhawk-1745015819

With most of these the problem is to prepare the aircraft for the flight, which even a professional fighter pilot cannot do alone. The actual taxi and taking off will be pretty easy even if unsafe (they crashed after all...).

@CarloFelicione I think this is more important than is let on with that incident " He was an accomplished glider pilot who set world records at a very young age"

The A-4 story link definitely needs to be added to this answer.

This is the stuff I was looking for.  All the way back to the 40's too!  Thanks.

I haven't flown for many years, but I remember my first experience was the surprise at how easy it was.
A small plane, say a Cessna 152, will practically fly itself; it feels like it wants to get off the ground.
90% of what one has to learn to take-off is running through check lists, doing safety checks, getting the weather forecast, plotting the course, and knowing radio protocol.  Someone stealing a plane could simply ignore all that.
Another 5% is learning to taxi to the runway.  Start the engine (much like a car), and use the foot pedals to steer.  Someone stealing a plane doesn't need to worry about brakes, or permission, or right-of-way; they can just go.  The only tricky part is knowing that the foot controls steer the opposite way to what one would expect (e.g. as on a soap-box go cart).
Assuming the thief can get the plane into position on the runway, it's simply a matter of giving it full power.  The plane will go, and it will take off, but only if one has the confidence to give the full power right away and not to ease into it as one would with a car.
Yes, it would be a lot easier and smoother if the flaps and trim are properly adjusted, but a small plane, with only the pilot aboard, will still take off, even if ungracefully.
Once it lifts off the ground, the only control needed is the "steering wheel", which again works just like in a car, but one can also pull or push on it to make the plane point down or up.  This is trivial to operate with almost no practice, so long as it is always done gently.
So yes, someone with no experience could get a plane into the air.  How long it would stay there before they over-reacted or panicked is a different question.  If they climb too fast, they'll stall and fall down.  If they're going too slowly when they turn, they'll enter a spin and fall down.  If they don't have complete confidence, they'll react badly to anything that happens, and fall down.
The movie acrobatics won't happen.  Flying like that requires real skill and experience.  If the pilot loses control, the plane will simply fall down.

I'd say that it completely depends on the type of airplane. Given enough surface and no obstacles in front of the airplane, then most airplanes wouldn't be difficult to get off the ground if you figured out how to add power and that more speed will make you fly. On the ground, steering with your feet might be weird at first, but pretty much anyone can figure that one out pretty quick, even under the stress of stealing a plane. I'd guess the hardest part would be the torque/p-factor encountered (or increased) after liftoff and what the purpose of the pedals is when you're off the ground. A P-51 would probably lose control pretty quickly without any skill on the rudder pedals, but something like a Cessna 152 is much more docile.
That said, if this was an Ercoupe (note: I've never flown it) then that aircraft is apparently known as being an incredibly easy aircraft to operate. It doesn't have rudder pedals and on the ground steers with the control yoke, like any car that the kid would definitely have seen. The controls are simplified and resemble a steering wheel more than they resemble a modern control yoke. Starting is apparently fairly simple. It's a low-wing aircraft, so it would get off the ground pretty easily. Handling characteristics are supposedly very tame in the air.
Again, I have never flown this aircraft, but given all of that, I would say that it would be extremely possible for a complete novice, even a young, untrained kid, to get off the ground.
https://www.aopa.org/go-fly/aircraft-and-ownership/aircraft-fact-sheets/erco-ercoupe

In my humble opinion, flying a small plane and sailing a small boat can be really easy when the conditions are good and the equipment is operational. A kid can do it and many kids already did. Both activities can become really complex and dangerous in a matter of seconds, and problems tend to appear all at the same time. That's why there is so much theory, training and check lists involved. But with some luck, it's perfectly possible to ignore them and live to tell.

" Both activities can become really complex and dangerous in a matter of seconds..." >> I've said it before and I'll say it again: In about 10-15 hours, I can teach (and have taught) anyone to take off and land an airplane quite safely in good conditions. But it's the thousands of hours after that where you really learn to be a pilot.

If you consider a disgruntled and/ or imbalanced airline employee as falling within the scope of your question, then a recent event in Washington state gives you your answer.   Except that you specify no simulator practice.
"Could they" may be speculative but I suppose a flight instructor could answer whether an unpracticed novice has ever successfully taken off with no instructions and no other hand touching controls.  This gives some insight as to what could be done by such a person with no one else in the cockpit.
Some planes have flown away by themselves, so maybe that's your answer.
That kid who stole several planes, did he have simulator practice before his first attempt?
Given the number of airplanes and airplane enthusiasts that have existed through the history of the world so far, the answer to your first question is almost certainly "yes".
Are you willing to consider within the scope of your question:
Ultralight airplanes?  I've seen books containg instructions on how to learn to fly by making short solo hops.  2-seaters were rare or non-existent when ultralights first became popular.
Hang gliders?  (Ditto from above)
Airplanes from the earliest pioneering days?  (Ditto from above)
"Primary" gliders?  -- a single-seat glider designed for training of novices, starting with short hops.  Popular in the 1930's.

I clicked through on this question just to answer that "some light planes will take off without even a pilot" or equivalent -- but you already had that in your answer.  Start the engine and throttle up (even just a little), release the brakes, and if the field is flat enough and wide enough, the airplane may just take off and fly around until it's out of fuel...

If I take the question title at face value, then my answer is yes, it is possible to take off.
As an untrained civilian, I've had the opportunity to hop into a few military flight simulators; and given sufficient runway, simply applying max MIL thrust in a modern fighter will have you lifting off (eventually) without too much effort if you can identify the throttle, without using flaps. (I'm completely ignoring the security considerations of sneaking into a military base and stealing a fighter. Not to mention, starting the engine without the ground cart.)
The same could almost apply for rotary wings, except for the complicated relation between the 3 controls. Simply pulling the collective 'killed' me until I realised the stick and pedals had to be coordinated as well.

Isn't a fighter one of the easiest planes to crash? A complete novice should probably try a Cessna instead.

@EricDuminil I have no real flying experience, so I wouldn't know. But it didn't seem too difficult to keep the fighters from crashing (in the sim anyway). Didn't try landing them, but OP's question was about taking off anyway =P

Yes, I did on my first (and only) flight lesson which I was gifted for my birthday.  The instructor let me take full control on take-off (he was hands-off from his controls) and I performed the landing myself.  Both from/to the main runway at Bournemouth International.  I was definitely an amateur and only 13 at the time!

You might mention whether or not the instructorcwas giving you verbal instructions.

Indeed, it had occurred to me that all pilots flew with no in-plane experience once.

@Exal: I am reminded of a quote from Wing Commander The Lord Flashheart - "Flash by name, Flash by nature!" - but due to the family-oriented nature of this site I shall avoid quoting it entirely. According to him, though, flying involves "...getting inside her..." - your aircraft, or "kite" - "...five times a day, take her to heaven and back". RIP Rik Mayall. Flasheart may have been an arrogant, racist, vain, self-absorbed boor of a character, but despite that we should also keep in mind that he had bad qualities, too.  :-)

Well said man, RIP !

As an addendum on that MST3K episode, has it happened before?  Yes on numerous occasions as the previous posts stated.  Some of these ad hoc flights ended safely, some didn’t.
As to whether someone could have stolen a GA aircraft from an FBO at KSFO, yes it’s quite feasible if the owner was careless and left it unlocked with the keys in it.  Ramps were quite accessible to the general public back in those days, and nobody asked a whole lot of questions.  So yes that’s realistic.
I would fetch a guest that a person with quite a bit of time in desktop flight simulators could probably acquire start up taxi and fly a light aircraft fairly easily, if only to save their hide. Landing may be a little tricky for them.
Next, could an airplane take off on a parking apron or taxiway?  A small one, like the Aircoupe there in the MST3K episode, yes.  Such and airplane would only need about 1000 ft or so of ground roll and a takeoff speed of 50 kts or so, so that’s realistic, even more so with someone who knew their way around an airplane at the controls.
As for being talked down to a safe landing, yes it has been done successfully in the past, though Parnell Roberts’ flying advice in the movie is complete BS.  Nor would someone maintain a close formation flight and attempt a formation landing with a neophyte at the controls of one of the aircraft.  Another pilot would give chase at a distance and follow behind during the landing.
So the sequence shown in the movie is somewhat realistic, though it is Hollywood and designed for entertainment.
“See those people down there?  Those are the people you’ve disappointed, Davy.”

Not exactly what I was asking for, but an interesting add-on.

A few years ago in Danbury, CT, an untrained man stole a single engine plane and flew it south to Westchester County Airport, a mid-sized airport just north of NYC He landed it successfully and was pomptly arrested. He was also drunk.
As for taking off at an airport like SFO without clearance, the only thing preventing that is fear of death.

It all depends on what the individual knows about flying in general and the aircraft type specifically.
There are stories of ground crew getting airborne, but although unlicensed/unqualified, they typically have familiarity with the type, and may even have operational experience starting/taxiing (e.g. the F-86 incident cited by fooot).
An individual having absolutely no familiarity with conventional aircraft controls or those specific to a given aircraft may have difficulty starting the engine and therefore not get very far.
It's quite easy to find information about aircraft specifics and flying in general without requiring any contact with a flight training establishment. One could learn from such materials the basic principles of flight, how to start a given aircraft, taxi it, and perform a take-off. However, absent of prior hands-on experience, things could start to go wrong as early as the take-off roll. Even though some airplanes are easy to fly and even "want to fly", a strong crosswind can easily ruin your day if you're not prepared for it - something that comes with at least a little experience. Some aircraft have handling issues around take-off; they can "get away" from a pilot lacking appropriate training and experience.
It's not hard to imagine that someone having only read the appropriate materials could, under favorable conditions, get an airplane airborne. What happens next is another matter.

Anyone who isn't employed as a pilot is by definition an amateur.
A very large number of people who fall in that category is either a pilot license holder or is (or has in the past) trained to become one.
All of those people can take off in an aircraft. And especially in the past many people did take off in aircraft without ever having had any training at all. They taught themselves to fly the hard way, by trying and see what worked. Of course a lot of those early pioneers ended up killing themselves in the process.
Now, if you're limiting your question to specific types or categories of aircraft you will limit that group further, as specific aircraft types may require knowledge that most of those people lack for how to prepare them for flight. Many may even require external equipment for them to be able to be started at all, meaning even a qualified pilot won't be able to do so without outside assistance.
But you didn't limit your question.

I disagree with the first sentence. I wouldn't call private pilots amateurs. Maybe "Anyone who doesn't hold a license that permits takeoff" or something would fit better?

@geisterfurz007 the first sentence is a statement of fact. There's nothing to agree or disagree with. The definition of amateur is someone who does something but doesn't get paid for it. A professional is someone who does something and gets paid for it, because it's their job, or profession (hence professional )

-1 if I could. This answer is word smithing amateur.  OP also says a civilian getting into a cockpit at SFO..., but I'm sure most commercial pilots are civilians.  He also uses the words layman, kid and zero experience.  He is clearly talking about someone not trained to fly a plane, not the technical definition of the word amateur.

@geisterfurz007: That sentence is literally the definition of "amateur". It seems that your native language is German, and in fact, in that language, the definition is exactly identical.

-1. What you say is technically correct, but it's pretty obvious that the question doesn't mean that.

I really don't think this phraseology is correct or useful in our context. Colloquially, at least, amateur strongly implies untrained, and perhaps even unskilled. Flying is pretty unique in that we have very strict rules, regulations and licensing. Similarly, somebody may not be a "professional" driver, but I've never heard anybody refer to an "amateur driver". Similarly, a fully trained volunteer firefighter is also an "amateur firefighter" by your definition, but again, it's unhelpful phrasology. Amateur / Professional works in certain fields, but here it's just confusing to use the term.

authors: Bob Jarvis - Слава Україні

authors: Vladimir F Героям слава


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Do lights on wingtips change color at different times of the day?
I have gone through this post which explained me why there are red lights turned on the plane but I doubt with the color code whether it's only during the environment specific conditions or its indication that it is relaying coordinates?
Every time one thing caught my attention during my flight journey. During the specific time of the day the lights on the wings changed with color.
On one flight it had a white constant blinking. This flight was during the day. The blinking was slow and repeated up to thrice.

On the second flight, there was a blinking green light along with the blinking white light. This blinking was fast so I couldn't get a clearer shot and this is during sunset.

Note:-In the above two images both are of the Airbus A320 Sharklet. I believe it has something to do with tracking and relaying the coordinates to the ATC.

Lights are not used for anything other than increasing visibility and awareness.  Nothing to do with tracking or "relaying coordinates".  Even if the aircraft did do this, light signals would be a lousy way to communicate the information.

@Simon just to be that guy, there are times when you communicate to ATC, or even other aircraft, via light flashes ;)

@SHAF Of course, you are right, but my comment was more to point out that they are not used for tracking (imagine the equipment that would need) nor for relaying co-ordinates, which would be kind of pointless since if you can see the lights, you already know where the aircraft is.

Every plane has green and white lights on the right (starboard) wing, as in this photo, and red and white on the left (port) wing. These lights are called "navigation lights," and are the same as are used in boating.
The green and red lights are always on, no matter what, and are used to help other aircraft know which direction the aircraft is going, based on whether the other pilot sees red, green or both lights.
The white lights are also on all the time, and flash constantly. These lights are called "anti-collision lights."

(Image Source: Wikipedia)
What you are actually seeing is the green light constantly on, and the white flashing - but because the white is so much brighter and is flashing, it's more apparent than the green (which, especially in the day, is fairly dim)
At night, the green becomes more obvious and the flashing white becomes more visible. The flashing white over-powers the green, which gives an optical illusion that the Green is flashing. The reality is that the Green is always on, and the white is flashing.

The anti-smash lights should be on anytime the engine is running, but strobes do not come on until you are ready to take the active, and nav lights aren't even required during the day in good weather.  Light usage varies by organization.

And by regulations

@jon as in the first image being a sharklet tip does it have anything to do with the make/class of wing structure

The sharklet probably affected the optical illusion part, as the lights are in slightly different places and the shape will affect how much of the White you can see